Loan Calculator — Monthly Payment, Interest & Amortization
Enter a loan amount, APR, and term to get the exact monthly payment, total interest, and total cost — using the same amortization formula every bank and dealership uses. Compare term lengths side-by-side and read the full month-by-month schedule. Free, 100% client-side.
Typical auto loan APR in 2026: 5–11% (2026 average for new vehicles)
Total paid
$36,068.31
Total interest
$6,068.31
Principal
$30,000.00
Interest / total
16.8%
Share of total cost
| Term | Monthly | Total interest | Total paid |
|---|---|---|---|
| 36 mo | $933.19 | $3,594.72 | $33,594.72 |
| 48 mo | $725.37 | $4,817.62 | $34,817.62 |
| 60 mo (selected) | $601.14 | $6,068.31 | $36,068.31 |
| 72 mo | $518.70 | $7,346.64 | $37,346.64 |
| 84 mo | $460.15 | $8,652.46 | $38,652.46 |
This calculator is for personal information only and is not financial advice. It assumes a fixed APR and standard amortization. Actual loan offers may include origination fees, prepayment penalties, or variable rates not modeled here.
Real Amortization Math
Uses the standard level-payment loan formula — monthly payment, total interest, total cost match what a bank quote would show, not a back-of-envelope approximation.
Term Comparison
Side-by-side comparison across multiple term lengths (e.g. 36/48/60/72 months) so you can see the trade-off between monthly affordability and total interest paid.
Full Amortization Schedule
Month-by-month breakdown of payment, interest portion, principal portion, and remaining balance. Watch your principal grow as interest shrinks.
100% Client-Side
Loan figures are sensitive — they stay in your browser. No signup, no API calls. Works offline once the page is loaded.
Loan Calculator: Monthly Payment, Total Interest & Schedule
A loan calculator turns three inputs — loan amount (principal), APR, and term in months — into your fixed monthly payment, total interest, and total cost. It uses the standard amortization formula, the same level-payment math behind every bank, credit-union, and dealership quote. Enter your numbers above to see the payment instantly, compare term lengths side-by-side, and read the full month-by-month schedule. Free and 100% client-side — your figures never leave your browser.
Estimates only — not financial advice. Results use a fixed-rate amortization model and may differ from a lender's quote, which can include fees, rounding, insurance, and variable rates. Consult a licensed professional or your lender for exact figures before signing any loan.
How to use this loan calculator
- Pick a loan type preset (auto, personal, student, or credit-card payoff) to seed realistic defaults, or skip straight to your own numbers.
- Enter the loan amount (principal) you plan to borrow.
- Enter the APR — use the lender's quoted annual percentage rate, not the headline interest rate, so fees are reflected.
- Choose the term in months; the calculator shows your payment plus a side-by-side comparison of nearby term lengths.
- Read the monthly payment, total interest, and total paid, then open the schedule to see interest and principal split for every month.
The exact amortization formula
This tool computes the fixed monthly payment with the standard amortization (level-payment) formula. It is the present-value-of-an-annuity equation, solved so the balance reaches exactly $0 on the final payment — no balloon, no shortfall.
M = P · [ r(1 + r)n ] / [ (1 + r)n − 1 ]Algebraically identical to the form this tool runs in code: payment = P · r / (1 − (1 + r)−n)
M= fixed monthly paymentP= principal (the amount borrowed)r= monthly interest rate = APR ÷ 12 ÷ 100 (e.g. 7.5% APR → r = 0.00625)n= total number of monthly payments = term in months
Edge case: when APR is exactly 0%, the formula reduces to M = P / n.
Worked example: $30,000 auto loan, step by step
Take the auto preset: principal P = $30,000, APR = 7.5%, term n = 60 months. Here is the arithmetic this calculator performs, ending at the number it displays.
- Monthly rate:
r = 7.5 ÷ 12 ÷ 100 = 0.00625 - Growth factor:
(1 + 0.00625)60 ≈ 1.45330 - Numerator:
0.00625 × 1.45330 ≈ 0.0090831 - Denominator:
1.45330 − 1 = 0.45330 - Payment:
M = 30000 × 0.0090831 / 0.45330 = $601.14
Monthly payment
$601.14
Total paid
$36,068.31
Total interest
$6,068.31
Total paid = $601.14 × 60 = $36,068.31; total interest = $36,068.31 − $30,000 = $6,068.31.
APR vs interest rate: enter the right number
The interest rate is the cost of borrowing the principal. The APR adds mandatory fees — origination charges, prepaid interest, sometimes insurance — into one all-in yearly rate, which is why it is usually higher than the bare interest rate. Enter the APR here so fees are reflected in your payment. By federal law (the Truth in Lending Act) lenders must disclose the APR, so when you compare offers, compare APR to APR — never APR to a headline interest rate.
"The APR is the interest rate plus any additional fees charged by the lender, including origination charges and other fees charged when the loan is made."— Consumer Financial Protection Bureau (CFPB)
What this calculator does not include
This is a pure amortization model. It assumes a single fixed payment, a constant APR, and that every payment lands exactly on schedule. Real loan costs can run higher because of factors the bare formula ignores: origination fees (commonly 1–5% of principal on personal loans), variable-rate adjustments, late or partial payments, compounding conventions (most US auto loans use simple monthly interest, but some lenders use daily simple interest, which shifts the totals slightly), and add-ons like GAP insurance or extended warranties rolled into the balance. If your lender quotes an APR that already bundles fees, the payment here will match closely; if they quote only the interest rate, your real all-in cost will be higher. Always reconcile against the lender's written Truth-in-Lending disclosure.
Loan vs Mortgage: Which Calculator Do You Need?
| Aspect | Loan Calculator (this page) | Mortgage Calculator |
|---|---|---|
| Typical Term | 12-84 months (1-7 years) | 15 or 30 years |
| Typical Principal | $1,000-$100,000 | $100,000-$1,000,000+ |
| APR Range (2026) | 5-28% depending on type & credit | 6.5-7.5% conventional, 30-year fixed |
| Collateral | Auto secured, others usually unsecured | Always secured by real estate |
| Extra Costs | Origination fee 1-5% | Escrow, PMI, points, closing costs |
| Use This Tool For | Car, debt consolidation, student loans | Home purchase or refinance |
Both calculators use the same amortization formula. The split is about defaults, term ranges, and what extras (escrow, PMI) you need to model.
How to Read the Amortization Schedule
1. Month 1 = Mostly Interest
On a $30,000 auto loan at 7.5% APR for 60 months, the first payment is ~$601 — of which ~$188 is interest and only ~$413 reduces principal.
2. Mid-Loan = 50/50 Crossover
Around month 30 (halfway), the interest and principal portions are roughly equal. Past this point, your payments work harder for you.
3. Final Month = Mostly Principal
The last payment on the same loan: ~$597 toward principal, only ~$4 in interest. Almost the entire amount is paying down the loan.
4. Total Interest = Cost of Borrowing
Sum of all interest rows. Compare across term lengths — a longer term means more rows, each with more interest. The trade-off has a price tag in dollars.
Loan-Shopping Best Practices
1. Compare APR, Not Just Rate
APR includes mandatory fees; the headline interest rate may exclude them. Always pivot to APR when comparing two offers.
2. Pre-Approval Before Shopping
Get pre-approved at your bank or credit union before walking into a dealership. Dealer financing is often 1-3% APR worse than a direct lender quote.
3. Avoid Longest Term You Can Afford
84-month auto loans exist; they almost always cost you. Pick the shortest term where the monthly payment is comfortably affordable — total interest savings compound.
4. Watch for Prepayment Penalties
Most modern auto and personal loans have no prepayment penalty. Some older mortgages and subprime personal loans do — read the contract before you sign.
Frequently asked questions
How is a monthly loan payment calculated?
With the amortization formula M = P · r / (1 − (1 + r)−n), where P is principal, r is the monthly rate (APR ÷ 12 ÷ 100), and n is the term in months. $30,000 at 7.5% APR over 60 months gives $601.14 per month. If APR is 0%, the payment is simply P ÷ n.
What is the difference between APR and the interest rate?
The interest rate is the cost of the principal; the APR adds mandatory fees into one all-in yearly rate, so it is usually higher. Enter the APR here, and when comparing offers, compare APR to APR — never APR to a headline rate.
Should I choose a shorter or longer term?
A longer term lowers the monthly payment but raises total interest. Pick the shortest term whose payment is comfortably affordable — under about 8% of monthly take-home pay is a useful ceiling.
Is my loan data sent to any server?
No. Every calculation runs in your browser in JavaScript — no fetch, no upload. Open DevTools, watch the Network tab, and you will see no requests fire. The tool also works offline once loaded.
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Last reviewed: June 2, 2026
Estimates only — not financial advice; consult a licensed professional or your lender for exact figures.
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